Bring a large pot of water to a boil. Salt generously and add pasta. Cook until al dente. Save a mug full of the pasta water before draining.

Meanwhile, melt the butter in a large saute pan. Add the shallot and cook until tender and lightly browned, 3-5 minutes.

In a separate bowl, whisk together the cream, egg yolk and lemon zest. Reduce the heat on the saute pan to medium-low, then whisk the cream into the shallot. Add in the cheese and whisk to combine. Continue to cook until slightly thickened, 2-3 minutes. Season with salt and lots of black pepper (to taste).

Stir the drained pasta into the sauce and stir to combine. Add reserved pasta water as needed to loosen the sauce. Serve with more pecorino, if desired.